1 Department of Gastroenterology, General Hospital of Shenyang Military Area, Shenyang, China; Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, China.
2 Department of Gastroenterology, General Hospital of Shenyang Military Area, Shenyang, China.
3 Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, China.